After downloading one of this website's ".zip" compressed ("zipped") files, you will need to decompress ("unzip") it to access the contents. The best way to do this is to run the zipped file through a program such as WinZip. But you don't have to use that one if you don't want to - there are many other programs available that will carry out the unzip (also sometimes called "archive extraction") correctly, as the ".zip" file format I have used for the compressed files is a world-wide standard. You may even find that your computer system already has an unzip/archive program or utility installed on it.